Field of the Invention
The present invention relates to a mobile radiation device having a set of each module required for the radiation imaging installed on a wheeled platform and particularly relates to the mobile radiation device having a power assist function.
Technical Background
Conventionally, the mobile radiation device used in the medical facility is a device having a set of each module required for the radiation imaging on the electrically movable wheeled platform. Typical modules installed to the wheeled platform are a radiation source that radiates radiation, a detection means that detects the transmissive radiation through the subject, and an image generation means that images the detected signals output from the detection means (refer to Patent Document 1, Patent Document 3, Patent Document 3).
Each module constitutes such mobile radiation device is installed on the handcart wheeled platform. When the operator needs to move the imaging device, the operator should push the wheeled platform to move. Despite a handcart type, each installed module is relatively heavy so that the wheeled platform has a power assist function.
Specifically, according to the conventional mobile radiation device, when the operator grips the bar installed to the wheeled platform and pushes, the wheeled platform senses the pressure to the bar so that the wheeled platform per se automatically moves according to the pressure. According to such structure, the operator can move the mobile radiation device with the sense as if operating the empty and light wheeled platform without a heavy load.
When the operator is moving the device by gripping the bar and tries to stop the move of the device, the operator operates a brake lever attached to the bar. When the brake lever is operated, the brake module installed to wheels of the wheeled platform becomes operative. The brake module is e.g., a drum brake that is operative to brake the rotation of the wheel by e.g., friction of the brake shoe. However, in such structure, the braking is too strong and the wheeled platform will jounce greatly. The procedural improvement relative to braking so as to control the jounce has been conventionally developed. Specifically, even when the operator turns the brake lever on, the brake module would not be immediately operative.
It is necessary to lower the velocity of the wheeled platform to some extent prior to turning the brake module operative to control the jounce due to braking. Specifically, when the operator operates the brake lever to stop the mobile radiation device, it must be controlled that the rotation of wheels of the wheeled platform firstly should be slowed down without turning the brake module operative. Such control can be achieved by controlling the motor driving wheels. And when the velocity of the wheeled platform is slowed down satisfactorily, the above brake module is turned operative. In such mode, the wheeled platform is realistically stopped through two steps including lowering the velocity with the motor control and braking with the brake module so that the mobile radiation device that does not jounce when stopping can be provided.
Accordingly, there is a need for an improved mobile-type radiographic image pickup device, and method and system for operating the same.